Using the ni Formula from a Paper with N=7: What do I Get?

In summary, the formula ni = (e^(B*(eH-ei))-1)*e^(-0.5772156649..) from the paper may be used to find values for n0, n1, n2, and n3 given that (n0,n1,n2,n3,n4,n5,n6,n7) = (3,2,1,1,0,0,0,0) for N=7. The paper also suggests using the approximation digamma(x+1) = ln(e^-m+x) where m = 0.5772156649. However, it may be difficult to match Boltzmann's combinatorial argument using this formula.
  • #1
rabbed
243
3
Hi

How do I use this formula:
ni = (e^(B*(eH-ei))-1)*e^(-0.5772156649..)
from this paper?
https://ui.adsabs.harvard.edu/abs/2018DDA...49P...2C/abstract
According to this site, (n0,n1,n2,n3,n4,n5,n6,n7) = (3,2,1,1,0,0,0,0) for N=7:
https://bouman.chem.georgetown.edu/S02/lect21/lect21.htm
Does that mean I should get:
n0 = (e^(B*(7-0))-1)*e^(-0.5772156649..) = 3
n1 = (e^(B*(7-1))-1)*e^(-0.5772156649..) = 2
n2 = (e^(B*(7-2))-1)*e^(-0.5772156649..) = 1
n3 = (e^(B*(7-3))-1)*e^(-0.5772156649..) = 1
?
 
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  • #2
cant open this paper. says: No Sources Found
 
  • #3
Yes, I can't find the actual paper either but that abstract (as well as another abstract from him) makes the derivation clear:

digamma(ni+1) = a-b*ei

use approximation digamma(x+1) = ln(e^-m+x) where m = 0.5772156649

ln(e^-m+ni) = a-b*ei

e^-m+ni = e^(a-b*ei)

ni = e^(a-b*ei)-e^-m
ni = e^(a+m-m-b*ei)-e^-m
ni = e^(a+m-b*ei)*e^-m-e^-m
ni = (e^(a+m-b*ei)-1)*e^-m
ni = (e^(a*((A+m)/b-ei))-1)*e^-m

replace eH = (a+m)/b

ni = (e^(b*(eH-ei))-1)*e^-m

I just can't get the ni's to match Boltzmann's combinatorical argument.
Shouldn't it be possible to find a B such that (n0,n1,n2,n3,n4,n5,n6,n7) = (3,2,1,1,0,0,0,0) for N=7?
 

1. What is the ni formula and how is it used?

The ni formula is a mathematical equation used to determine the sample size needed for a study with a given population size. It takes into account the desired level of precision, confidence level, and standard deviation of the population. It is commonly used in research and statistical analysis to ensure accurate and representative results.

2. What does the "N=7" in the ni formula refer to?

The "N=7" in the ni formula refers to the population size. This is the total number of individuals or elements in the group being studied.

3. How do I calculate the ni value using the formula?

To calculate the ni value, you will need to plug in the values for precision, confidence level, and standard deviation into the formula: ni = (Zα/2 * σ / ε)^2. Zα/2 represents the critical value for the desired confidence level, σ is the standard deviation of the population, and ε is the desired level of precision.

4. Can the ni formula be used for any population size?

Yes, the ni formula can be used for any population size. However, it is most accurate for larger population sizes. For smaller populations, it is recommended to use a different formula or consult with a statistician.

5. What is the significance of using the ni formula in research?

Using the ni formula in research ensures that the sample size is appropriate and representative of the population being studied. This helps to minimize errors and increase the reliability and validity of the study's findings.

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